Methods and apparatus for non-uniform temporal cardiac imaging

Abstract

A method for imaging a heart of a patient utilizing a CT imaging system includes steps of assigning a scanning priority to phases of a representative cardiac cycle of the patient's heart, selecting phases of the cardiac cycle for scanning in accordance with the assigned scanning priority, and obtaining image slices of the patient's heart corresponding the selected phases of the cardiac cycle. The method can be performed by a CT imaging system including an EKG machine to record EKG data.

What is claimed is:  
     
       1. A method for imaging a heart of a patient utilizing a CT imaging system, said method comprising the steps of: 
       assigning a scanning priority to phases of a representative cardiac cycle of the patient's heart in accordance with cardiac volume distances from a baseline volume;  
       selecting phases of the cardiac cycle for scanning in accordance with the assigned scanning priority; and  
       obtaining image slices of the patient's heart corresponding the selected phases of the cardiac cycle.  
     
     
       2. A method in accordance with  claim 1  further comprising obtaining EKG data of the patient's heart, and wherein assigning a scanning priority in accordance with cardiac volume distances from a baseline volume comprises the step of assigning a priority to local maxima and minima of the heart volume in accordance with heart volumes indicated by the EKG data. 
     
     
       3. A method in accordance with  claim 2  wherein obtaining EKG data of the patient's heart comprises the steps of recording a plurality of complete cardiac cycles of the patient's heart and computing the representative cardiac cycle of the patient's heart utilizing the plurality of complete cardiac cycles. 
     
     
       4. A method in accordance with  claim 3  wherein computing the representative cardiac cycle comprises the step of averaging the plurality of complete cardiac cycles. 
     
     
       5. A method in accordance with  claim 2  wherein obtaining image slices of the patient's heart comprises performing a cine scan of the patient's heart. 
     
     
       6. A method in accordance with  claim 2  wherein assigning a scanning priority to phases of a representative cardiac cycle of the patient's heart comprises the step of assigning a scanning priority in accordance with cardiac volume distances from a baseline volume and also in accordance with temporal and spatial gradients of the cardiac data. 
     
     
       7. A method in accordance with  claim 6  further comprising the step of interpolating between at least a pair of selected phases to select an additional phase for scanning. 
     
     
       8. A method in accordance with  claim 2  and further comprising the step of filtering the EKG data in accordance with criteria selected to reduce temporal and spatial noise. 
     
     
       9. A method in accordance with  claim 2  wherein at least one of the selected phases is a phase corresponding to a baseline volume of the patient's heart. 
     
     
       10. A method in accordance with  claim 1  and further comprising the step of displaying data as animated image frames, wherein a number of identical frames F to display for each phase P n  is written as: 
       
         
             F =(Pos( P   n+1 )−Pos( P   n ))× FR,    
         
       
       where: 
       F=a number of phases displayed for phase n;  
       P n =a phase n;  
       Pos(P n )=a temporal position of phase n; and  
       FR=a display frame rate.  
     
     
       11. A method in accordance with  claim 10  wherein displaying data as animated image frames comprises the step of displaying frames consisting of one image slice. 
     
     
       12. A method in accordance with  claim 10  wherein displaying data as animated image frames comprises the step of displaying frames comprising a plurality of image slices representing different planes at a single phase of the patient's cardiac cycle. 
     
     
       13. A CT imaging system for imaging a heart of a patient, said imaging system including a radiation source and detector configured to rotate in an imaging plane around the patient, the detector being configured to sense the projected x-rays that pass the heart of the patient, said imaging system configured to: 
       assign a scanning priority to phases of a representative cardiac cycle of the patient's heart in accordance with cardiac volume distances from a baseline volume;  
       select phases of the cardiac cycle for scanning in accordance with the assigned scanning priority; and  
       obtain image slices of the patient's heart corresponding the selected phases of the cardiac cycle.  
     
     
       14. A system in accordance with  claim 13  further configured to obtain EKG data of the patient's heart, and wherein said system being configured to assign a scanning priority in accordance with cardiac volume distances from a baseline volume comprises said system being configured to assign a priority to local maxima and minima of the heart volume in accordance with heart volumes indicated by the EKG data. 
     
     
       15. A system in accordance with  claim 14  wherein said system being configured to obtain EKG data of the patient's heart comprises said system being configured to record a plurality of complete cardiac cycles of the patient's heart and to compute the representative cardiac cycle of the patient's heart utilizing the plurality of complete cardiac cycles. 
     
     
       16. A system in accordance with  claim 15  wherein said system being configured to compute the representative cardiac cycle comprises said system being configured to average the plurality of complete cardiac cycles. 
     
     
       17. A system in accordance with  claim 14  wherein said system being configured to obtain image slices of the patient's heart comprises said system being configured to perform a cine scan of the patient's heart. 
     
     
       18. A system in accordance with  claim 14  wherein said system being configured to assign a scanning priority to phases of a representative cardiac cycle of the patient's heart comprises said system being configured to assign a scanning priority in accordance with cardiac volume distances from a baseline volume and also in accordance with temporal and spatial gradients of the cardiac data. 
     
     
       19. A system in accordance with  claim 18  further configured to interpolate between at least a pair of selected phases to select an additional phase for scanning. 
     
     
       20. A system in accordance with  claim 14  configured to filter the EKG data in accordance with criteria selected to reduce temporal and spatial noise. 
     
     
       21. A system in accordance with  claim 14  wherein at least one of the selected phases is a phase corresponding to a baseline volume of the patient's heart. 
     
     
       22. A system in accordance with  claim 13  further configured to display data as animated image frames, wherein a number of identical frames F to display for each phase P n  is written as: 
       
         
             F =(Pos( P   n+1 )−Pos( P   n ))× FR,    
         
       
       where: 
       F=a number of phases displayed for phase n;  
       P n =a phase n;  
       Pos(P n )=a temporal position of phase n; and  
       FR=a display frame rate.  
     
     
       23. A system in accordance with  claim 22  wherein said system being configured to display data as animated image frames comprises said system being configured to display frames consisting of one image slice. 
     
     
       24. A system in accordance with  claim 22  wherein said system being configured to display data as animated image frames comprises said system being configured to display frames comprising a plurality of image slices representing different planes at a single phase of the patient's cardiac cycle.